Question

The different varieties of coal differ in their:
A.Carbon content
B.Moisture
C.Ratio of carbon and hydrogen present
D.Volatile nature

Answer 1

Coal has 4 different varieties, depending on its stages of formation. The organic dead plant material goes beyond earth's surface under high pressure and temperature to get converted into fuel, called coal. This conversion of dead organic soft material into the most pure form of coal has 4 stages or 4 different varieties according to its increasing carbon content.

Complete step by step answer:
As we already know, the formation of coal takes place in earth’s crust, under high pressure and high temperature by burial of dead organic plant matter. So this process takes place in 4 stages, which are also called as 4 varieties of coal.
Coal is made up of Carbon, hydrogen, oxygen and nitrogen compounds. The organic material is deposited, due to high pressure and temperature increases in their carbon content, and moves from soft coal to the purest form of coal.
The coal formation takes place in 4 stages and each stage or variety has different carbon content which mainly are called peat, lignite, bituminous, and anthracite.

So, the correct answer is Option A .

Additional Information:
The 4 varieties of coal, with their properties and carbon content are briefly discussed as under:
1.Peat: It is the primary stage of coal formation, and it is just soft organic dead plant matter with some deposited minerals with least carbon content of 40-50 %. It is brown in colour. It is the youngest soft type of coal.
2.Lignite: This is the second stage of coal formation which is brown in colour and also called as brown coal. It has carbon content of 60-70%, and sometimes used in electricity generation, etc.
3.Bituminous: This is the third stage of coal formation, and the coal formed is used in household purposes, electricity generation and has a higher carbon content of 70-80%. The appearance is also smooth and shiny.
4.Anthracite: This is the final stage of coal formation with maximum carbon content of 80-99%, and this is most used in industrial purposes to generate a high amount of energy. This is considered the highest and purest form of coal.

Note:
Allotropes of carbon are different from types of coal. Allotropes are different arrangements of Carbon atoms while different varieties of coal are due to its different carbon content. There are other properties of variation also, in these different types of coal, but the major difference is in their carbon content. The increasing order of carbon content in 4 varieties of coal are: peat < lignite < bituminous < anthracite.